Organic material (e.g., blood clots, tissue, and biological concretions such as urinary, biliary, and pancreatic stones) or inorganic material (e.g., components of medical devices or other foreign matter) may sometimes obstruct or otherwise be present within the body's anatomical lumens, such as the biliary tree. For example, biological concretions can develop in certain parts of the body, such as kidneys, pancreas, and gallbladder. Minimally invasive medical procedures generally involve causing limited trauma to the tissues of the patient, and can be used to dispose of certain problematic biological concretions or similarly unwanted obstructions.
In addition, lithotripsy and ureteroscopy, for example, may also be used to treat biological concretions (e.g., kidney stones) in the body of patients. Lithotripsy is a medical procedure that uses energy in various forms, such as acoustic shock waves, pneumatic pulsation, electro-hydraulic shock waves, or laser beams, to pulverize biological concretions such as urinary calculi (e.g., kidney stones). The force of the energy, when applied either extracorporeally or intracorporeally, usually in focused and continuous or successive bursts, divides the concretion into smaller fragments that may be extracted from the body, or allowed to pass from the body, for example, through urination.
In certain instances, intracorporeal fragmentation of bodily concretions can become problematic if the stones or stone fragments, instead of progressing out of the patient's body, begin to migrate further into the body or towards an organ. In these circumstances, further medical intervention to prevent aggravation of the patient's condition may become necessary. Therefore, it may be desirable to be able to extract such fragments from the body using a single instrument, preventing the need for successive instrumentation which can cause greater trauma to the patient's tissues.
Many medical retrieval devices can be used to entrap an object, such as a stone fragment, and drag it through an ampulla (i.e., a small dilatation in the patient's anatomical lumen) to remove it. Such medical retrieval devices include, for example, retrieval baskets and may be used through an endoscope or laparoscope. However, occasionally an object may be too large to be extracted through an ampulla, or an obstacle is encountered upon forward movement of the stone fragment within the anatomical lumen. It may be necessary to provide further treatment, for example, lithotripsy or surgery.
With many known retrieval assemblies, it is difficult to release entrapped material, such as a stone, from the retrieval assembly once the material is entrapped. For example, in some patients, a cicatrix or some other constriction that reduces the diameter of a body lumen may form within the lumen. The narrowed lumen may not interfere or prevent normal insertion of a retrieval device. However, after the retrieval device is inserted into the tract, the retrieval assembly expands, and an object is captured within the device. At this point, the diameter of the retrieval assembly containing the entrapped object may exceed the inner diameter of the narrowed lumen. Under these circumstances, it may be desirable to release the entrapped object from within the retrieval assembly so that the retrieval assembly may be safely removed from the lumen. Other circumstances may be encountered during a medical retrieval procedure that may also require releasing an entrapped object from the retrieval device.
The present disclosure provides medical retrieval devices and methods of using the same that address some or all of the aforementioned shortcomings of the existing devices.